Personal watercraft (PWC) have become increasingly popular in recent years. A personal watercraft, also known as a “jet ski” typically has a bottom hull, handle bars for steering, a tunnel within the bottom hull, a jet pump located within the bottom tunnel, and an engine within the hull under the top deck for driving the jet pump. The jet pump typically pulls in water from the front of the tunnel under the boat, and discharges the water at high velocity through a steerable nozzle at the rear of the boat. The handlebars are typically coupled to the nozzle, which is the steering mechanism for the personal watercraft. The watercraft commonly has a straddle-type seat and foot wells disposed on either side of the seat.
Personal watercraft typically have a top deck affixed to a bottom hull. The PWC has a shroud mounted in front of the driver on top of the top deck to house the steering column and some instruments. A front portion of the top deck includes a hinged cover or “hood.” The underside of the hood can include a gasket or a grommet that attempts to provide a watertight seal between the hood and the top deck. The hood typically covers either a storage bin or an engine access port.
Personal watercraft often have a “rub rail” that can serve as a bumper around the boat. The rub rail can be wrapped around the outer extent of the top deck, to protect the top deck from damage from other boats or docks alongside. Rub rails ideally have some give or resiliency. This resiliency can be provided with a complex lateral or transverse profile. Some such rub rails have an outer wall over a central channel, or a pair of cantilevered wings that provide the resiliency. Rub rails are generally formed using one of two methods. Extrusion can be used to form straight sections of rub rail. A die for the extrusion process can cost on the order of 10,000 dollars, or less. Where straight sections of rub rail are not appropriate, injection molding can be used to form complex curves and rear corner pieces. Injection molds can cost on the order of 100,000 or 200,000 dollars, depending on the complexity. Injection molds cannot easily be used to form certain lateral or transverse shapes. In particular, injection molding cannot easily be used to form a profile that cannot be pulled from the mold, for example, profiles having a central channel or converging cantilevered wings.
Personal watercraft typically have an outer periphery or bow line. This periphery can be formed by the coming together and bonding of the bottom hull to the top deck. Some personal watercraft have a “horizontal bond line”, resulting from the top deck and bottom hull extending horizontally and outwardly together over a horizontal segment in which the top deck and bottom hull are bonded together. A rub rail to protect and cover this horizontal bond line can function as a cap, having an upper lip extending over the top deck to support the rub rail and hold it in place. Such a rub rail can have a bottom lip extending under the bottom hull segment as well.
Other watercraft have a “vertical bond line”, resulting from the top deck extending downward to terminate in a vertically downward segment. The bottom hull can extend upward to form the hull along the waterline, then extend further upward, then outward in an upside down “U” shape, then downward to terminate in a vertically downward segment alongside and inside of the outer top deck vertically downward segment. The vertically downward segments of the top deck and bottom hull are said to form the vertical bond line.
The vertical bond line typically has a top deck outer vertical surface on which to mount the rub rail. Most vertical bond lines do not provide an upper ridge on which to hang or support the rub rail. The rub rail is typically secured with fasteners of some sort. Rub rails secured to vertical bond flanges are usually, if not always, formed of a rigid material. Forming such a rub rail out of a flexible or even a semi-rigid material can lead to a very soft rub rail after the rub rail has been in direct sunlight for a period of time. If hot and soft enough, the rub rail can even be pulled from and over the fasteners, away from the watercraft. For this reason, rub rails for vertical bond flanges are typically made from rigid polymers, to avoid this tearing and to avoid sagging of the rub rail.
Rigid rub rails can present a problem in that they do not conform to complex surface geometries as easily as semi-rigid or flexible. In particular, vertically curved or bow lines have been difficult to protect with rigid rub rails. Also, rear corners have been difficult to protect with rigid rub rails. One solution has been to make the rub rails for complex curves or corner pieces using injection molding. Injection molding suffers from the cost disadvantage discussed above. Injection molding also can limit the rub rail to shapes that have limited resiliency. Finally, the discrete rear corner pieces formed by injection molding can form a gap or discontinuity where they meet the side rub rail pieces and can be snagged as the discontinuity catches on docks, even pulling the rub rail away from the watercraft. A continuous extrusion could be used that wraps around the rear corners, but current rub rails, if flexible enough to wrap around the rear corners, tend to both wrinkle and to sag on the vertical bond flange.
What would be desirable are watercraft designs that do not require separate rear corner pieces. What would also be desirable are rub rails that are rigid enough to be used on vertical bond flanges without sagging, can be formed using extrusion, and can wrap around rear corners and protect personal watercraft hulls over vertical curves.